Extending Ceiling Joists

[leevis]

Hi All
My house has a separate bathroom and toilet and I wish to knock the wall down in between these to make one big open space.

We recently had a loft extension and it would appear that the ceiling joists for the bathroom have been cut so that they rest on the dividing wall. There are currently no joists above the toilet but there is a steel about half way across.

My plan was to extend the existing joists somehow and use joist hangers on the steel to support these joists. One the other side they will be new joists going via a joist hanger from the steel onto the existing wall.

I would say that the extension of the existing joists would be around 30cm and the additional bit on the other side of the steel would be the same.

The width of the bathroom currently is around 2m.

Any ideas on how to extend? I have read that a new timber screwed with 12mm coach bolts (3) with an overlap of 1200mm would suffice but I think that this sounds a bit too much.

Any ideas?

 

[RonnyRaygun]

1200mm overlap is definitely more than you need. There are a number of factors to take into account such as the length of span and depth of joist, and loads carried, but if you have minimum 150mm deep joists then 400mm overlap with four M10 bolts at 300mm horizontal and 100mm vertical centres will be OK.

 

[^woody^]

... 2 bolts and spur connectors?

 

[RonnyRaygun]

... 2 bolts and spur connectors?

Maybe...if I get a minute I'll do a check...

-------------------------------------------------------

I found a minute...

Based on a 3m joist span...two M12s with 51mm square TPCs both sides of bolts.

Wasn't sure if OP meant span of joists was 2m??

Alternatively the bolt centres can be increased to reduce load on them and come down to M10s.

 

[leevis]

TPCs?

 

[RonnyRaygun]

TPCs?

Tooth Plate Connectors.

What is the span and depth of your joists?

 

[leevis]

The existing span is about 1.8 meters, moving to a further 1 meter (probably less) so the total length would be around 2.8 meters tops (more like 2.3 meters).

I cant see the depth of the existing at the moment because I will have to remove the toilet ceiling which I plan to do on Saturday. I believe that they are no more than 4 inches though. It is worth nothing that there is nothing above these joists ie they are just holding up the ceiling/lighting

 

[leevis]

I think I might be getting confused, joist length is around 1.8 moving to 2.8. The width of the room is about 2.3 meters

 

[cjard]

Is it possible to fit a steel (or even a timber beam) where the wall will be removed and have it carry the joists? I think it would be far less messing around than extending every joist

 

[leevis]

There is a steel already there but its around 30-40cms too short of the joists, the only way really will be to extend and hang on the steel i think

If i get timber the same size / or larger i should be able to join using the 2 coach bolts and the TPC in between, how long should i overhang? 400mm i think was posted before

 

[cjard]

I meant to fit another beam rather than extend the joists. What does the existing steel carry currently?

 

[leevis]

The steel is carrying the joists in the loft extension. I could attach hangers to the steel but the joists would still not meet the hangers

 

[leevis]

Hi All
Revisiting this one
Just cut a largish hole in the ceiling to see whats going here and here are my measurements:
The length of the joists are about 1800mm in length and they stop short of the steel by around 50mm
My plan is to hang a hanger into the steel and bridge the gap of 50mm but screwing another joist (existing is 100mm but i have some 140mm timber here)
The questions i have are:
1) how long should the joist be that i am screwing to the side of the existing? (1200mm?)
2) what size bolts should i use, i have some turbo coach screws here which are M10 (10mm thick) but not sure if they are the right size
3) are tooth plate connectors really required?
4) how many bolts in this length will be needed and at what centers?
Many thanks
Lee
Doing this right now so any advice would be greatly appreciated

 

[leevis]

OK, i am about to rip the rest of the ceiling down this weekend once i get the bath out to give me some adequate space to get in there.
I am going to extend these joists into the steel and hang the ends on hangers, i will be using 1200mm unless anyone can give me a better number to be dealing with on this one, there are 6 joist that i need to extend and the length of the existing is 1800mm which will be extended 50mm into the hanger. If this distance can be reduced (I am sure it can but not sure to what distance) then it would be great to know this.

I will then have a second problem, the joist sits over the toilet area meaning that i will have to hang some other joists onto the other side of the steel (about 400mm), this isnt really a problem as this should provide a decent enough base for hanging the new ceiling onto. However, i was thinking of getting hold of some studwork timber and securing this around the whole room about 10mm lower than the existing joists and then using large frame fixings to secure onto the wall, once the frame is build, use hangers to hand additional bits of studwork timber onto these to give me a proper decent base to secure the ceiling to. This way the plasterboard would be level and it would be easier to put up. Whats everyones thoughts on this? would this be a viable prospect or would it be better just to hang the ceiling onto the existing joists?
L

 

[cjard]

You know.. It's a lot of dicking around for the sake of buying a few new timbers that are the right length and at a couple of quid a metre the collective time of writing this thread has probably cost more.

Move the steel over by 50mm to catch the ones that fall 50mm short, or bolt a 50mm timber onto the side of the steel and nail hangers to it. Buy new joists for the other side that is well short (you've confusingly gone from 1.8m to 2.8m to 2.3m to 50mm over he course of the thread. Pictures next time please) and keep the old joists for use elsewhere in your project. Or log burner